Related

EDMONTON — As people with pollen allergies (sniff) already know, botanical sexism is alive and growing.

Most North American cities plant more male bushes, trees and plants than their female counterparts. They do this because pollen-producing male trees don't bear fruit or make seeds that drop on the ground the way female trees do.

The mess the females create can clog drains and create sewage problems, cause people to slip and fall — the city would be liable for injuries — and attract wildlife and wasps.

The sexual imbalance makes for a cleaner-looking city, but it also creates a pollen-saturated environment, says California horticulturalist and author Thomas Ogren. All this pollen causes a sensitivity in people that can eventually lead to an allergy and this, he says, partly explains the rise in urban pollen allergies.

Seasonal allergies, also known as hay fever, are very common, affecting about 15 per cent of the population, says Dr. Harissios Vliagoftis, an allergist in the University of Alberta's Department of Medicine and a board member of the Lung Association Alberta & NWT.

Ogren is right that allergies have been increasing over the last 15 to 20 years in developed countries, he notes. There are several immunological theories as to why, including the hygiene theory, that our immune system doesn't get stimulated enough when we're young because our environments are too clean.

"Because of that, our immune system doesn't learn how to respond correctly to all the external stimuli and that's why allergies develop," Vliagoftis explains.

"I don't know how much things would change if we change the way we plant trees because there is not very good data on how much pollen you need to get sensitized, but during the times of year when pollen counts are high, (and male trees make pollen), allergic people do have more problems," Vliagoftis says.

Yet none of the 10 Canadian cities Ogren's researched and plans to visit this spring — including Edmonton where he arrives on March 30 — takes this into account when landscaping, Ogren says.

Jenny Wheeler, the city's principal of forestry, was allergic to blooming sage brush when she lived in Medicine Hat, Alta., so she understands what it's like to have a hard time breathing because of pollens. But people have to learn to live with nature, she says.

Ogren, a past consultant with the U.S. Department of Agriculture and author of several books including Safe Sex in the Garden and Allergy-Free Gardening, says there's a better solution: plant more (single-sex) female trees to attract the pollen produced by males, or plant trees with both male and female parts, since the pollen doesn't spread as much.

A growing number of American cities have pollen-control bylaws that forbid the sale or planting of certain plants and trees, he notes, after a six-year-old boy playing with friends at a zoo in Albuquerque, N.M., fell face first into a planting of junipers, got a large dose of pollen and died. The boy's family successfully sued the city.

"If Edmonton is worried about lawsuits from somebody slipping on seeds, down the road there's going to be other lawsuits about the systematic planting of things that make people sick," predicts Ogren, who has provided expert testimony in several such cases.

During his time in Edmonton, Ogren will evaluate the city's allergen levels and landscape planting practices, present and future, which will be included in a report commissioned by allergy-medication maker Reactine. He'll also visit schools to see what they're planting and nurseries to see what they're stocking. He expects to have the audit finished by June, with the hope that it may influence cities and their residents to include allergies in their thinking about plant selection.

"The common thing I'm hearing (from cities) is their tree plan is 10 to 15 years old, and when it was adopted, allergies weren't even on their radar," Ogren said on the phone last week, during a stop in Vancouver.

Edmonton grower Ken Riske says hardly anybody he knew had allergies 30 years ago. But now at least once a day somebody shopping at his nursery raises the issue. Usually, they're sensitive to birch, poplar, willow or oak pollen.

That's why it's important, if using a landscaper, to let them know what not to plant in your yard, says Riske, who also suggests telling neighbours of your plans, in case they're allergic to what you're planning to put in.

Edmonton came up on Ogren's radar when he came across a website advising people in Edmonton not to plant female willow or poplar trees because of the mess. He began exchanging emails with Wheeler who says she looks forward to his visit and what the city can learn from his findings that could help more Edmontonians enjoy the outdoors.

The practice of planting more male plants began with poplars and poplar fluff, Wheeler explains.

"A lot of people would have allergies around the same time, and because they could see the poplar fluff, they associated it with their allergies."

Further study found that poplar fluff is actually hypoallergenic, something that surprises angry residents with allergy symptoms who complain about it to the city every June. But while poplar fluff doesn't cause allergies, there are a lot of other plants that bloom at the same time that do arouse symptoms, Wheeler says.

Some people call to complain about having to clean up after messy plants, such as elm trees, which have both male and female parts and produce seeds. Some people ask to have a tree removed, says Wheeler.

"We're trying to increase our tree canopy (double its size from 10 per cent to 20 per cent), so if we remove trees just because they produce seeds, we also lose the benefits and enjoyment of what those trees do."

The better solution is thoughtful planning, she says.

"If it's a more natural type setting, (like the river valley) we could probably put more female plants into those sorts of areas, but in parks, playgrounds and boulevards, stick with males."

Comments

We encourage all readers to share their views on our articles and blog posts. We are committed to maintaining a lively but civil forum for discussion, so we ask you to avoid personal attacks, and please keep your comments relevant and respectful. If you encounter a comment that is abusive, click the "X" in the upper right corner of the comment box to report spam or abuse. We are using Facebook commenting. Visit our FAQ page for more information.

Almost Done!

Postmedia wants to improve your reading experience as well as share the best deals and promotions from our advertisers with you. The information below will be used to optimize the content and make ads across the network more relevant to you. You can always change the information you share with us by editing your profile.

By clicking "Create Account", I hearby grant permission to Postmedia to use my account information to create my account.

I also accept and agree to be bound by Postmedia's Terms and Conditions with respect to my use of the Site and I have read and understand Postmedia's Privacy Statement. I consent to the collection, use, maintenance, and disclosure of my information in accordance with the Postmedia's Privacy Policy.

Postmedia wants to improve your reading experience as well as share the best deals and promotions from our advertisers with you. The information below will be used to optimize the content and make ads across the network more relevant to you. You can always change the information you share with us by editing your profile.

By clicking "Create Account", I hearby grant permission to Postmedia to use my account information to create my account.

I also accept and agree to be bound by Postmedia's Terms and Conditions with respect to my use of the Site and I have read and understand Postmedia's Privacy Statement. I consent to the collection, use, maintenance, and disclosure of my information in accordance with the Postmedia's Privacy Policy.